xargs or gnu parallel for parallel processing

[ch604]

would be nice to run multiple digs at once, to the capacity of the server. the loop for the blacklist would need to be functionized and then passed to either parallel or xargs

[ch604]

made a quick fork and mockup with gnu parallel, and the time savings is immense, though there are some bugs with output numbers.

in parallel:

real	0m20.673s
user	0m10.001s
sys	0m6.378s

not in parallel:

real	3m2.151s
user	0m7.252s
sys	0m8.817s